A storage area network (SAN) has significantly changed the manner of storing and accessing data from a conventional local database, such as file servers, to a remote network of its own. With the increasing amount of data to be stored, the local database associated with a computer is no longer capable of storing all the data. The SAN has solved the problem by providing a network of storage that allows the multiple servers to share and access from separate networks of their own. The SAN is a dedicated and centrally managed information infrastructure that primarily provides communications and data transfers between computer nodes or interconnected devices, such as disks and tapes, storage nodes, servers or other devices. The SAN facilitates multiple users to access and share a pool of storage servers. Management of these types of systems plays an important role to secure the data access (i.e., who is authorized to access the data or who can access which devices and at what point in time.)
Fiber channel is a primary technology used in more recent SAN systems. Due to their high-speed, fiber channels enable the SAN to interconnect between servers and storage devices at data transfer rates of up to 200 Mbps in a dual loop configuration or 100 Mbps in a redundant mode. Typically, a fiber channel can be configured in various ways, such as a point-to-point configuration, a fiber channel arbitrated loops (FC-AL) configuration, and a switched fiber channel fabrics (FC-SW) configuration. The point-to-point fiber channel is a simple way to connect two devices directly together. The FC-AL includes a set of hosts and devices that are connected into a single loop. The FC-AL can support up to 126 devices and hosts on a single loop. In FC-SW, devices are connected in many-to-many topology using fiber channel switches. In this configuration, the number of devices that can be connected is unlimited.
A switched fiber channel fabrics FC-SW configuration employs at least one switched fiber channel fabric. A switched fiber channel fabric (or hereinafter “fabric”) is a collection of fiber channel switches that connect the individual devices in the many-to-many topology. A storage fabric is a collection of the many fiber channel switches that connect the individual devices (e.g., hosts, nodes) in a SAN. With all of the data stored in a single, ubiquitous cloud of storage, controlling which hosts have access to what data is extremely important. Zoning, in this respect, provides an isolation boundary for such management.
Zoning may be employed to group devices according to operating system, application, function, physical address, or other criteria as needed. Zoning separates the SAN into logical sub-networks. A port (e.g., host adapters or storage controller ports) can be configured as part of a zone. A port may separate a zone, or a SAN into physical sub-networks. The storage fabric may be configured so that only ports in a given zone can communicate with other ports in the same zone. Typically, zoning is implemented at the port level with zone access controlled by the ports configured to allow access or prevent access in the fabric, or zoning is implemented using simple name server (SNS) software that operates on the fabric switch. With zoning implemented using a SNS software, a node is identified using the node's world wide name (NWWN) and a port is identified using the port's world wide name (PWWN). Using SNS a defined zoning table may be developed listing devices by availability within a specific zone, and accessibility by a specific list of hosts. In either zone implementation when a host entity attempts to connect to a SAN and requests a list of available storage devices, the host will only receive access data for those storage devices that the host was configured to receive through a specific port configuration, or a defined zoning table.
Although the zoning in the SAN segregates storage access, zoning implicitly binds the technology of SAN (e.g., servers and storage arrays that can access each other through managed port-to-port connections). Devices within a specific zone can recognize and communicate with each other, but may not be able to with devices in other zones, unless a device in that zone is configured for multiple zones. Hence any change in the SAN topology may affect the localized zone or zones, and any change within a zone may affect SAN topology.
Due to the characteristics of the zoning in the SAN, there exist a number of problems in conventional SAN management. Certain devices may be required for specific zone deployments and configurations. In deployments supporting very important data storage, redundant devices (e.g., secure servers or hubs) provide added reliability and security, and assist with maintaining a zone's integrity. In addition to security and protective features, specific deployments may have certain devices configured for specific internal routines (e.g., redundant disk arrays for rapid data recovery). For example, when a node in the SAN becomes non-functional, replacing the non-functional node may disturb the overall zone integrity, especially if a replacement node is not available. With any change in a particular entity, for example changing from a functional node to a non-functional node, another entity will directly or indirectly perceive the change. Oftentimes, a change in a particular entity is promptly corrected, especially when the resources exist within the dedicated local area. However, with larger and more complex architectures, often containing many different systems specifically designed to operate separately, prompt management and resolution architectures are not always available, and changes in a particular entity might cause significant operational problems affecting an entire network or collection of network resources. Even when operational problems affect only a small amount of network resources, the changes may cause deleterious effects to the associated zone integrity.
What is needed is a system and method that relates generally to Topology-Static (TS) architecture within a computer system, and more particularly to the improved management of a Topology-Static architecture.